Digital control of telephony has led to advancement of intelligent network standards for the public switched telephone network (hereafter the "PSTN"). As viewed herein, the PSTN is the aggregate world-wide of all instrumentalities operating to interconnect telephones used by members of the public at large (both land-based and cellular/radio type telephones), but excluding privately deployed facilities which serve specific users or corporate employees (e.g. private networks formed by PBX's, Centrexes, etc.) as well as public data networks such as the Internet, World-Wide Web, etc.
A problem with the present call management infrastructure of the PSTN is that its controls of user services (particularly services relating to voice announcements and speech recognition) tend to be tightly concentrated on a centralized basis; stemming from the need to ensure that switched call traffic is not potentially disrupted by commands originating from different places. However, this makes it awkward, impractical or sometimes impossible to introduce new user services without affecting the handling of call traffic during the introduction. Furthermore, administration of such services also tends to be tightly concentrated, so that PSTN users requiring changes in their services have very limited options; for instance, a user having "call waiting" service can only disable that service during individual calls, and only by pre-dialing a special set of symbols (e.g. "*70") as a subset of the called number.
The present invention seeks to provide improvements to the call management and administrative infrastructure of the PSTN, which is both adaptive to introduction of new services, without potential disruption of existing call traffic, and also broadens user options for enabling and disabling services to which they subscribe so that such services can be enabled or disabled virtually at any time (before and during individual calls) and their status (of enablement or disablement) can be maintained virtually for any length of time, or any number of calls, that a user desires to specify. This improved user interface further tends to allow for the introduction of new services which would have been impractical to offer or maintain in the prior infrastructure.